Colloquium, 5 March 2008, 3:00 pm, EN6085A

Analyses of Cloud Microphysics from Cloud Radar and Lidar

In this talk ship-based radar and lidar observations of clouds are analyzed.  The vertical cloud structure in the Tropics and mid-latitudes are considered and the drizzle frequency is derived. Regional differences in vertical features are also discussed. The cloud fraction, radar reflectivity factor and lidar backscattering coefficient are simulated along the cruise track with a combined aerosol transport model and GCM (SPRINTARS). The comparison of observation and the model output show that the model significantly overestimates cloud fraction above 8km. The model also overpredicts the frequency of convection reaching the upper atmosphere above 12km and underpredicts low-level cloud occurrence; drizzle frequency is overestimated.

Space borne radar (CloudSAT) and lidar data (CALIPSO) are also examined. For this we develop a cloud mask. The application of cloud mask is crucial for CALIPSO to exclude dust and noise from clouds.  Then we apply the radar/lidar algorithm to derive ice effective radius and ice water content (IWC). The retrieved microphysics is validated with the in-situ data.